According to a new study from the Netherlands, supplements of essential fatty acids, vitamins and minerals may reduce the number of violent and aggressive episodes among young adult offenders.

Dutch researchers recruited 221 prisoners, aged between 18 and 25, and randomly assigned the participants to one of two groups. One group was given a selection of capsules comprising fish oil, evening primrose oil and micronutrients for one to three months, while the other group was given placebo pills.

Before supplementation, the subjects were asked to complete a number of questionnaires, designed to assess their health and aggression levels. Members of prison staff were also asked to rate the level of hostile and aggressive behaviour using a special aggression scale. At the end of the supplementation period, the questionnaires and ratings were repeated. In addition, all recorded incidents of violence or rule-breaking behaviour for the participating prisoners were gathered for a period of one month before the trial started as well as during the trial.

When the results were analysed, the researchers found that the number of violent incidents had reduced by 34% in those taking the nutritional supplements, compared to the 14% reduction seen in those taking the placebo pills.

Commenting on their results, the researchers wrote: “The prospect of influencing aggression and rule-breaking behaviour with nutrients in moderate doses is important enough to warrant further research.

This is particularly true as adequate supplementation may also have beneficial effects on mental health and cognitive functioning.”